Asterism

Overview

An Asterism is a collection of Source objects representing multiple guide stars (NGS and/or LGS). It can be coupled to a Telescope in place of a single source, enabling multi-source and tomographic AO simulations.

When an asterism is coupled to a telescope and an atmosphere, each source in the asterism receives an independent OPD slice computed from the atmosphere layers, accounting for each source’s altitude and sky coordinates.

Quick start

from OOPAO.Source import Source
from OOPAO.Asterism import Asterism

src_on  = Source('H', magnitude=8, coordinates=[0, 0])
src_gs1 = Source('R', magnitude=9, coordinates=[30, 0])
src_gs2 = Source('R', magnitude=9, coordinates=[30, 120])
src_gs3 = Source('R', magnitude=9, coordinates=[30, 240])

ast = Asterism([src_gs1, src_gs2, src_gs3])

# Propagate through the chain — relay() called on each source independently
ast * tel * wfs

# Reset all source EM fields and optical paths, then propagate
ast ** atm * tel * wfs

API reference

class OOPAO.Asterism.Asterism(list_src)

Collection of Source objects for multi-source simulations.

Parameters:

list_src (list[Source]) – List of Source objects. May mix NGS and LGS types.

Key properties

src: list[Source]

List of constituent source objects.

n_source: int

Number of sources in the asterism.

coordinates: list

Sky coordinates [radius, angle] of each source.

wavelength: float

Wavelength of the first source (used for reference).

tag: str

Always 'asterism'.

Operator summary

Expression	Effect
ast * obj	Call obj.relay(src) for each source in the asterism
ast ** obj	Reset EM field and optical path for each source, then relay
ast * tel * wfs	Propagate all sources through telescope then WFS
ast ** atm * tel * wfs	Full reset + atmosphere + telescope + WFS for all sources